Atomistic Defect Interactions in Aluminum, Copper and Nickel: Edge Dislocations and 〈112〉-Axis Symmetric Tilt Grain Boundaries
Li Li, Lijun Liu, Yoji Shibutani
The interactions between edge dislocations and 〈112〉-axis symmetric tilt grain boundaries (GBs) in Al, Cu and Ni were analyzed by molecular dynamics simulations. Absorption, transmission and pile-up were all observed while absorption is the dominant phenomenon, especially in Al. The leading partial dislocation was spontaneously absorbed into the GB without any resistance, as was even the trailing partial dislocation in Al for the high-energy GBs. However, for all the GBs in Cu and Ni, further external shear loading was necessary to trigger the defect interactions. Σ11A GB requires the largest shear stress to trigger the absorption of trailing partial dislocation, and the other GBs follow a general trend that the critical shear stress would decrease as the GB energy increases since the low-energy GB shows a more stable state. For the most stable GB of Σ11A in Al, Cu, Ni, and the further addition of Au and Pd, the critical interaction shear strain to trigger the interaction is proportional to a physical parameter which is based on the difference between the unstable and stable stacking fault energies.